Automatic transmission clutch plates are flat annular rings having a friction lining applied to the annular sides. One or both sides are often covered with an annular ring of friction material lining sized for mating engagement with adjacent plates similarly lined. A lubricating medium such as transmission oil may communicate with the lined outer sides of the clutch plates in the clutch plate assembly to control engagement of the adjacent clutch plates. The friction lining was often similarly shaped as an annular ring and the annular ring is cut from sheet material. However, removal of an annular ring from a sheet material leaves a substantial portion of sheet material residue, for example, the circular internal portion and triangular outer portions of the sheet material. As a result, a substantial amount of the sheet of friction material is wasted during the production and assembly of lined clutch plates.
One previously known assembly eliminates the large areas of waste by cutting the friction lining as arcuate segments. However, the previously known process provided arcuate segments having interlocking end portions so that the segments are interconnected for accurate alignment on the sides of the annular ring forming the clutch plate. This interconnection and alignment assures proper installation of the friction lining on the side surface of the clutch plate ring. However, the interconnection of the segments complicates installation of the lining on the plate ring, since each segment must be handled so as to avoid disconnection of the interlocking tabs and slots of the friction lining segments. The connection forms an annular ring of separatable but interconnecting segments that must be transferred simultaneously to the side of the clutch plate ring. Moreover, the friction material must be modified before or after installation to include grooves, for example, by hot molding a plurality of parallel grooves in the friction material sheet, to provide fluid passages for lubrication communication between radially inner and outer edges of the clutch plate.
In addition, the previously known arcuate segments were shaped to conform with the shape of the annular ring. Accordingly, the outer radius of each arcuate segment is larger than the inner radius of the arcuate segment, conforming to the shape of the adjacent edges of the annular clutch plate ring to which the segments are applied. Thus, each arcuate segment must be spaced from an adjacent position of a segment to be cut from a friction material sheet to accommodate the different radii of adjacent curves. As a result, even when the segments are aligned closely adjacent each other, an amount of material must separate adjacent cuts. Accordingly, previous arcuate segment cutting limits the opportunity to reduce waste of the material used to form segments from a single sheet as numerous areas of wastage occur on each sheet between the segments to be cut from such an alignment on the sheet. Moreover, the arrangement and alignments of segments on each sheet may be diverse when the arrangement is configured to improve utilization of the friction material in the sheet. Cutting such diverse cutting paths can be extremely time consuming or require expensive software controls. In addition, complex arrangements or orientations of segments within the sheet can complicate handling, alignment and placement of the segments on a disc. The cost savings from use of the sheet material may be outweighed by the cost to deliver or align segments for attachment around an annular disc, and the difficulty of handling segments in a cost effective production operation.
In addition, it has also been known to extrude a long strand of friction material having a relatively small cross-section. The strand is then sliced into multiple small segments that can be applied to a clutch plate ring. However, such a structure substantially multiplies the number of pieces that must be formed, located and adhered to the ring. Accordingly, such an assembly can increase the opportunity to misalign the segments with respect to the annular shape of the ring and the adjacent segments. In addition, such a construction limits the ability to configure communication passages as spacings between the sliced segments and limits surface area of exposed friction lining.